Cellulose organic ester composition containing pinacol



Patented Apr. 9, 1935 UNITED: STATES 11 Claims. (Cl. 1ll640) This invention relates to compositions of matter in whichcellulose organic esters, such as cellulose a'cetate,. are combined or mixed with other substances, such as a compatible plasticizer, with 5 or without a common solvent for both, and with or without other useful addition agents, so that the resulting productwill have properties such as will make the composition highly advantageous for use in the plastic and analogous arts, such, for instance, as---the manufacture of wrapping sheets or tissue, photographic film, molding compounds and products, artificial silk, varnishes or lacquers, coating compositions and the like.

One object of this invention is to produce compositions of matter which may be made into permanently transparent, strong and flexible sheets or films'of desired thinness which are substantially waterproof, are unaffected 'by ordinary photographic fluids and possess the desired properties of a support for sensitive photographic coatings. Another object of my invention is to produce compositions of matter which are ca pable of easy and convenient manipulation in the plastic and'analogous arts, suchas in the manufacture of .sheets, films, artificial silk filaments, varnishes, lacquersand the like, and to produce compositions which will not injure, or be injured by, the substances or surfaces with which theyare associated during manufacture. Another object of my invention is to produce compositions which can be molded at elevated temperatures and high pressures to produce 'pla s tic products having the desirable properties of celluloid. Still another object of my invention is to produce compositions of matter containing cellulose acetate which have a high degree of flexibility, softness and pliability; Other objects will become apparent to those skilled in the art to which this invention pertains;

While cellulose acetate has been known for decades, it has also been known that to'utilize it in the various plastic arts it is necessary to mix therewith various plasticizing or conditioning agents. Certain of these and other addition agents are also added for the purpose of reducing the infiammability of the product. Plastic inducing agents, such as the higher alcohols'and their esters, are sometimes also added. :Similarly, addition compounds of various kinds have been employed to increase flexibility, transparency, toughness and otherproperties which will enhance the value of the resulting product. Addition products for the same or similar purposes are also added to cellulose acetate to prepare it for use in the other plastic arts, such as in the manufacture of lacquers-varnishes, artificial silk filaments, molded compounds and the} like, While the plasticizers or other addition agents heretofore discovered have.hadtheirutilitydn the art, the increasing use tov which cellulose 5 acetate has been put and the increasing number of desirable propertieszrequired of cellulose" acetate for most purposes have made the discovery of new and economical plasticizerslor other addition agents a matter ofponsiderable importance to theart. This has been a problem of some difficulty, since'many of thenitrocellulose solvents are not solventsfor cellulose acetate,

and many substances which act as plasticizers for nitrocellulose are not compatible or at least not-.sufiiciently compatible with cellulose acetate to be'used as plasticizers in cellulose acetate compositions. r

I have discovered that valuable properties may be induced in and/ or contributed to compositions containing. organic esters of cellulose, such as cellulose-acetate, by adding thereto as a plasticizer, a. compound selected from the group consisting of pinacol and pinacol hydrates The particularly useful properties which these compounds induce in or contribute to cellulosiccompositionscontaining themare hereinafter enu-' merated. a

In order that those skilled in this art 'may better understand my invention I would state, by way of illustration, that for the manufacture of photographic film base or'other-sheets' my new compositions of matter may be compounded as follows: 100 parts or; acetone-soluble cellulose acetate, i. e. cellulose acetate containing from about 36% to 42% acetyl radicaLapproximately,

is dissolvedwithstirring at atmospheric temperature in 300 to 500 parts, preferably 400 parts, by weight, of acetone; To this solution may be added from 10 to parts by weight of pinacol or of pinacol hydrate. Within the limits stated, the amount of plasticizer may be decreased or increased, depending upon whether it is desired to decrease or increase, respectively, the properties which these plasticizers contribute to the finished product. The amount of solvent em:- ployed may also be increased or decreased, depending. upon whether it is desired to have a more or less freely fio'wingcomposition, respectively. I v A composition of matter prepared as above described may be deposited upon any suitable film-forming surface and the acetone evaporated therefrom to form a film or sheet, in a manner, well known ,to those skilled in the art. A filmso ENT OX'FFICE.

. greater than V cizer. Furthermore, film 'soplasticized maintains of pinacol (30to50 parts by weight per l00parts' by weight of cellulose acetate) had an initial flexibility of from 165% to 300% greater than that of film containing no plasticizer, and films containing from 10% to 50% ofpinacol hydrate had an initial fiexibility'from 135% to 265 that of film containing no plastiflexibility in a superior fashion. 'For'instance, at 65 C., films containing from 30% to 50% of pinacol maintained flexibility for 303 days, and" films plasticized with from 10% to 50% or" pinacol hydrate maintained flexibility for 389 days,

whereas an unplasticized film became brittle in a 30; days. This indicate's that films or sheets'so plasticized will withstand .ordinaryl'usage satisfactorily for many years.

Other similar solvents (instead of acetone) which are compatible with the cellulose acetate and my new plasticizers will also occur to those skilled in this art, such as ethylene chloride-a1- cohol mixtures. In like manner these plasticizers may be compounded With othersingle organic esters of cellulose, such as cellulose propionate, butyrate, stearate and'the like, or with mixed organic esters, such asxcellulose aceto-stearate,

cellulose aceto-propionate, cellulose aceto-buty rate, cellulose aceto-lactate, cellulose aceto-tartrate or the like, a suitable solvent which will dissolve both the cellulosic derivative and the plasticizer being employed, such, for instance, as. Y an alkylene chloride with or without the addition of alcohol.

Inasmuch as my. above-described compositions of matter are useful in the production of films and sheets, it will be apparent that my new plasticizers mayalso be employed with advantage in the other branches of the plastic art. For in-' stance, my novel. plasticizers may be employed" in connection with a number of the known lacquer and varnish formula: with which they may be found to be compatible. In such cases the plasticizer is usually first put into'solution in the cellulose derivative solution, and if non-solvents are addedfor. the purpose of cheapening the composition they are added only to such an extent as will not precipitate the derivativefrom solution. Other uses within the scope of my. invention will also suggest themselves to those skilled in the art and are to be included'within the scope of the claims appended hereto.

. i-finacol and pinacol hydrate may alsolbe advantageously used as plasticizers incellulose organic ester molding compositions. For instance, when about 30% (30 parts by Weight per parts of'cellulose acetate). of pinacol is homogeneously mixed with cellulose acetate, the mixture may be"v converted. into .a hard, transparent or transhomogeneously mixed with cellulose acetate, the mixture may be converted into a hard, transparent or translucent plastic product by molding at a temperature of C., approximately, and a pressure of 2500 to 4000 pounds per square inch for a period of from 2 to 5 minutes.

' Moreover, I have found that, upon the addition to cellulose acetate of approximately 100% of pinacol or of pinacol hydrate, quite unexpected compatibility of the plasticizer with the cellulose acetate exists and'also that quite unexpected flexibility, plasticity and clarity of the final product result. ;Contrary to experience in most cases where suc'h'a large proportion of plasticizer is used, no exudation or crystallizing out of the plasticizer occurs. While here and in certain of the appended claims I have referred to the use of a plasticiz er in approximately equal proportions, namely in a ratio of approximately 100%, itwill be understood that within this terminology from the group consisting of pinacol and pinacol hydrate.

2. A composition of matter comprising cellulose acetate and a compound selected from the group consisting of pinacol and pinacol hydrate.

3. A composition of matter comprising cellulose acetate and pinacol.

4. A composition of matter comprising cellulose acetate and pinacol hydrate.

5. A composition of matter comprising 100 parts of cellulose acetate and from 5 to 100 parts, by weight, of a compound selected from the group consisting of pinacol and pinacol hydrate.

6. A transparent, flexible sheetcomprising 100 parts of a cellulose organic ester and, as a plasticiser therefor, about 10 to 55 parts, by weight,

of a compound selected from the group consisting of pinacol and pinacol hydrate.

'7. A transparent, flexible sheet comprising 100 parts of cellulose acetate and, as a plasticizer therefor, about 10 to 55 parts, by weight, of a compound selected from the group consisting of pinacol and pinacol hydrate.

3. A transparent, flexible sheet comprising 100 parts of cellulose acetate and about 10 to 15 parts, by weight, of pinacol. 1

9. Atransparent, flexible sheet comprising 1.00

parts of cellulose acetate and about 10 to 55 parts, by weight, of pinacol hydrate.

10. A molding composition adapted for molding under elevated temperatures and high pressures, comprising a, cellulose organic ester and a compound selected from the group consist-ing of pinacol and pinacol hydrate.

11. A molding composition adapted for molding under elevatedtemperatures and high presb sures, comprising cellulose acetate and a compound selected from the group consisting of pinacol and pinacol hydrate.

HENRY SMITH. 

